U.S. patent number 5,060,774 [Application Number 07/396,544] was granted by the patent office on 1991-10-29 for temperature-controlled fan fluid coupling.
This patent grant is currently assigned to Usui Kokusai Sangyo Kaisha Ltd.. Invention is credited to Yuichi Ono, Kazunori Takikawa.
United States Patent |
5,060,774 |
Takikawa , et al. |
* October 29, 1991 |
Temperature-controlled fan fluid coupling
Abstract
There is disclosed a temperature-controlled fan fluid coupling
which supplies cooling air to the engine of an automobile according
to the operating conditions at all times. The coupling includes a
rotating shaft, a driving disk fixed to the shaft, and an enclosed
housing consisting of a cover and a casing. The coupling further
includes a dam for collecting oil, a circulation passage, a valve
member for opening and closing a hole formed in a partition plate,
and a temperature-sensing element. Radially protruding fins or
recessed walls are formed to force oil to the dam.
Inventors: |
Takikawa; Kazunori (Numazu,
JP), Ono; Yuichi (Numazu, JP) |
Assignee: |
Usui Kokusai Sangyo Kaisha Ltd.
(Sunto, JP)
|
[*] Notice: |
The portion of the term of this patent
subsequent to January 10, 2006 has been disclaimed. |
Family
ID: |
26448714 |
Appl.
No.: |
07/396,544 |
Filed: |
August 21, 1989 |
Foreign Application Priority Data
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Aug 19, 1988 [JP] |
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63-108898[U] |
Aug 19, 1988 [JP] |
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63-108899[U] |
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Current U.S.
Class: |
192/58.681;
192/82T; 192/58.7 |
Current CPC
Class: |
F16D
35/022 (20130101) |
Current International
Class: |
F16D
35/00 (20060101); F16D 35/02 (20060101); F16D
035/00 (); F16D 043/25 () |
Field of
Search: |
;192/58B,58A,82T
;123/41.12 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0279271 |
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Aug 1988 |
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EP |
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3719279 |
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Mar 1988 |
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DE |
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55-76226 |
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Jun 1980 |
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JP |
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57-167533 |
|
Oct 1982 |
|
JP |
|
57-179431 |
|
Nov 1982 |
|
JP |
|
62-124330 |
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Jun 1987 |
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JP |
|
Primary Examiner: Bonck; Rodney H.
Attorney, Agent or Firm: Casella; Anthony J. Hespos; Gerald
E.
Claims
What is claimed is:
1. A temperature-controlled fan fluid coupling comprising:
an enclosed housing consisting of a cover and a casing;
a rotating shaft having a driving disk fixed at the front end of
the shaft one surface of the driving disk being in radial mesh with
an opposite wall surface of the enclosed housing to form a
labyrinth mechanism;
a bearing via which the housing is held to the rotating shaft;
a partition plate that is provided with an oil outflow control hole
and divides the inside of the housing into an oil reservoir chamber
and a torque transmission chamber in which the driving disk is
mounted;
a dam formed in a part of the inner wall surface of the housing and
opposite to the outer wall of the driving disk on which oil is
collected during rotation;
a circulation passage connected with the dam and extending from the
torque transmission chamber to the oil reservoir chamber;
a temperature-sensing element which is installed on the front
surface of the cover and deforms as temperature varies; and
a valve member which interlocks with the temperature-sensing
element and which, when the ambient temperature exceeds a
predetermined temperature, opens the outflow control hole in the
partition plate and which, when the ambient temperature is below
the predetermined temperature, closes the outflow hole, the torque
transmitted from the rotating shaft to the driven enclosed housing
being controlled by increasing and decreasing the effective area
with which oil makes contact with the driving disk at a torque
transmission gap formed between opposite outer walls of the casing
and the cover; and
an oil supply means formed on one of the surfaces of the housing
and the driving disk opposite of the labyrinth and at the entrance
side of the circulation passage to force oil to the dam.
2. The temperature-controlled fan fluid coupling of claim 1,
wherein the oil supply means comprises radially protruding
fins.
3. The temperature-controlled fan fluid coupling of claim 1,
wherein the oil supply means comprises recessed walls.
4. The temperature-controlled fan fluid coupling of claim 1,
wherein the oil supply means comprises radially protruding fins and
recessed walls.
5. A temperature-controlled fan fluid coupling comprising:
an enclosed housing consisting of a cover and a casing;
a rotating shaft having a driving disk rigidly fixed at the front
end of the shaft;
a bearing via which the housing is held to the rotating shaft;
a partition plate that is provided with an outflow control hole and
divides the inside of the housing into an oil reservoir chamber and
a torque transmission chamber in which the driving disk is
mounted;
a dam formed in a part of the inner wall surface of the housing and
opposite to the outer wall of the driving disk on which oil is
collected during rotation;
an annular idle oil reservoir chamber provided in the enclosed
housing and located radially outside the dam and in communication
with the torque transmission chamber;
circulation passage connected with the dam and extending from the
torque transmission chamber to the oil reservoir chamber;
a temperature-sensing element which is installed on the front
surface of the cover and deforms as temperature varies; and
a valve member which interlocks with the temperature sensing
element and which, when the ambient temperature exceeds a
predetermined temperature, closes the outflow control hole, the
torque transmitted from the rotating shaft to the driven closed
housing being controlled by increasing and decreasing the effective
area with which oil makes contact with the driving disk at a torque
transmission gap formed between opposite outer walls of the casing
and the cover; and
a multiplicity of radially protruding fins (16) or recessed walls
(16') on the wall surface of the driving disk (7) of the enclosed
housing near the outer periphery of the disk (7) and at least on
the side of the dam (12).
6. The temperature-controlled fan fluid coupling of claim 5,
wherein the fins (16) or the recessed walls (16') are disposed at
least on the upstream side of the dam (12) as viewed in the
direction of rotation.
7. The temperature-controlled fan fluid coupling of claim 5,
wherein a portion of each fin (16) spaced from the driving disk is
made substantially flush with the inner side surface of the
enclosed housing.
8. The temperature-controlled fan fluid coupling of claim 5,
wherein the fins (16) or the recessed walls (16') are inclined at
an angle from a radial direction and protrude axially.
9. The temperature-controlled fan fluid coupling of claim 5 wherein
the fins (16) or the recessed walls (16') are formed on a side of
the driving disk (7) and opposite to a labyrinth mechanism of the
driving disk (7).
10. The temperature-controlled fan fluid coupling of claim 5,
wherein said fins (16) or the recessed walls (16') extend into the
idle oil reservoir chamber (14).
11. A temperature-controlled fan fluid coupling comprising:
an enclosed housing consisting of a cover and a casing;
a rotating shaft having a driving disk rigidly fixed at the front
end of the shaft;
a bearing via which the housing is held to the rotating shaft;
a partition plate that is provided with an oil outflow control hole
and divides the inside of the housing into an oil reservoir chamber
and a torque transmission chamber in which the driving disk is
mounted;
a dam formed in a part of the inner wall surface of the housing and
opposite to the outer wall of the driving disk on which oil is
collected during rotation;
an annular idle oil reservoir formed on an inner wall surface of
the housing radially outside the dam, the idle oil reservoir
chamber being in communication with the torque transmission
chamber;
a circulation passage connected with the dam and extending from the
torque transmission chamber to the oil reservoir chamber;
a temperature-sensing element which is installed on the front
surface of the cover and deforms as temperature varies; and
a valve member which interlocks with the temperature-sending
element and which, when the ambient temperature exceeds a
predetermined temperature, opens the outflow control hole in the
partition plate and which, when the ambient temperature is below
the predetermined temperature, closes the outflow control hole, the
torque transmitted from the rotating shaft to the driven enclosed
housing being controlled by increasing and decreasing the effective
area with which oil makes contacts with the driving disk at a
torque transmission gap formed between opposite outer walls of the
casing and the cover; and
a multiplicity of radially protruding fins (7') formed near the
outer periphery of the driving disk (7).
12. The temperature-controlled fan fluid coupling of claim 11
wherein the outer periphery of the driving disk is of reduced axial
thickness, each fin (7') extends axially from the reduced thickness
portion of the driving disk to be flush with the torque
transmission surface of the driving disk (7) radially inwardly from
the reduced thickness portion of the driving disk.
13. The temperature-controlled fan fluid coupling of claim 11,
wherein each fin (7") protrudes from the torque transmission
surface of the driving disk (7).
14. A temperature-controlled fan fluid coupling comprising:
an enclosed housing consisting of a cover and a casing;
a rotating shaft having a driving disk fixed at the front end of
the shaft;
a bearing via which the housing is held to the rotating shaft;
a partition plate that is provided with an oil outflow control hole
and divides the inside of the housing into an oil reservoir chamber
and a torque transmission chamber in which the driving disk is
mounted;
a dam formed in a part of the inner wall surface of the housing and
opposite to the outer wall of the driving disk on which oil is
collected during rotation;
an annular idle oil reservoir chamber formed in the inner wall
surface of the housing radially outside the dam, the annular idle
oil reservoir chamber being in communication with the torque
transmission chamber;
a circulation passage connected with the dam and extending from the
torque transmission chamber to the oil reservoir chamber;
a temperature-sensing element which is installed on the front
surface of the cover and deforms as temperature varies;
a valve member which interlocks with the temperature-sensing
element and which, when the ambient temperature exceeds a
predetermined temperature, opens the outflow control hole in the
partition plate and which, when the ambient temperature is below
the predetermined temperature, closes the outflow control hole, the
torque transmitted from the rotating shaft to the driven enclosed
housing being controlled by increasing and decreasing the effective
area with which oil makes contact with the driving disk at a torque
transmission gap formed between opposite outer walls of the casing
and the cover; and
radially arranged convex walls (7 or 7', 7") formed at least on one
of both side surfaces of the driving disk (7) radially inside the
torque transmission gap.
15. The temperature-controlled fan fluid coupling of claim 14,
wherein the vicinities of the outer wall surface of the driving
disk (7) are in radial mesh with opposite wall surface of the
enclosed housing to form a labyrinth mechanism.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to improvements in a
temperature-controlled fan fluid coupling which controls the
rotation of a fan that cools an automotive engine by supplying an
appropriate amount of cooling airflow to the engine always
according to the operating conditions.
2. Description of the Prior Art
A conventional fan fluid coupling of this kind is shown in FIG. 13,
where an enclosed housing is comprised of a cover 23' and a casing
23". The inside of the housing is partitioned into an oil reservoir
chamber 25 and a torque transmission chamber 26 by a partition
plate 24 provided with an outflow control hole 24'. A driving disk
22 is mounted inside the torque transmission chamber 26, which is
in communication with the oil reservoir chamber 25 via a dam 28
acting as a pumping portion. A circulation passage 27 extends from
the dam 28 and has an entrance port 27' and an exit port 27". In
order that at least one of these ports be located above the level
of the oil in the oil reservoir chamber 25 irrespective of the
stopped condition, the exit port 27" is formed at the open end of a
substantially arc-shaped groove 29 communicating with the
circulation passage 27. The groove 29 is formed by holding a
partition wall around the inner wall surface of the oil reservoir
chamber 25.
In this prior art fan fluid coupling, if the circulation passage 27
is submerged in the oil inside the oil reservoir chamber 25 when
the vehicle is at rest, oil is prevented from spontaneously flowing
back into the torque transmission chamber 26 from the reservoir
chamber 25 through the passage 27 to prevent collection of oil
inside the transmission chamber 26. In this way, the rotational
speed of the fan is kept from increasing violently immediately
after the engine is started. Therefore, abnormal fan noise is
prevented. Also, during cold weather the engine is effectively
warmed up. When the engine is operating at high temperatures, the
outflow control hole 24' in the partition plate 24 is opened by a
valve member, and this hole 24' is submerged in the oil stored in
the oil reservoir chamber 25. Under this condition, if the engine
is stopped, then oil spontaneously flows out of the chamber 25
through the outflow control hole 24' and a large amount of oil is
collected in the torque transmission chamber 26 while the engine is
at rest. Accordingly, if the engine is then restarted, the
rotational speed of the driven fan increases after the lapse of a
certain time as indicated by the performance characteristic curve B
in FIG. 14.
In the aforementioned prior art fan fluid coupling, only the
centrifugal force produced by rotation forces oil out of the torque
transmission gap of the torque transmission chamber and so oil
flows slowly through this gap. Heat is produced by shear for a long
time, thus elevating the temperature of the oil. Also, the oil is
not quickly circulated through the coupling. Since a sufficient
amount of heat is not conducted to the outside, the viscosity of
the oil changes, or drops. As a result, the fluid coupling fails to
act adequately in response to the ambient temperature. Further,
hunting takes place possibly because oil does not smoothly flows
into the circulation passage due to oil pressure variations around
the dam. In addition, the aforementioned increase in the rotational
speed of the driven fan occurs for some time.
SUMMARY OF THE INVENTION
In view of the foregoing problems with the prior art techniques,
the present invention has been made. It is an object of the
invention to provide a fan fluid coupling free of the foregoing
problems. In particular, during rotation, supply of oil from the
torque transmission gap to the dam is accelerated by the guiding
action performed by an oil supply means, or fins or grooved walls,
as well as by the centrifugal force acting on the oil itself. This
enhances the functions of the dam. Generation of heat due to shear
for transmission of torque is suppressed greatly and, therefore,
the temperature of oil increases to a lesser extent. Oil is quickly
circulated through the whole internal structure, resulting in good
heat dissipation. Hence, the viscosity of the oil is less likely to
change, or drop. Also, hunting is prevented. In this way, the fan
coupling is capable of controlling the transmitted power more
appropriately in response to the changing ambient temperature.
The above object is achieved by a fan fluid coupling comprising: an
enclosed housing consisting of a cover and a casing; a rotating
shaft having a driving disk rigidly fixed at the front end of the
shaft; a bearing via which the housing is held to the rotating
shaft; a partition plate that is provided with an oil outflow
control hole and divides the inside of the housing into an oil
reservoir chamber and a torque transmission chamber in which the
driving disk is mounted; a dam formed on a part of the inner wall
of the housing and opposite to the outer wall of the driving disk
on which oil is collected during rotation; a circulation passage
connected with the dam and extending from the torque transmission
chamber to the oil reservoir chamber; a temperature-sensing element
which is installed on the front surface of the cover and deforms as
temperature varies; and a valve member which interlocks with the
temperature-sensing element and which, when the ambient temperature
exceeds a predetermined temperature, opens the outflow control hole
in the partition plate and which, when the ambient temperature is
below the predetermined temperature, closes the outflow control
hole. The effective area with which oil makes contact with the
driving disk at a torque transmission gap formed between opposite
outer walls of the casing and the cover is increased and decreased
to control the torque transmitted from the rotating shaft to the
driven enclosed housing. This fan fluid coupling is characterized
in that an oil supply means is formed in at least one of the
opposite surfaces of the housing and the driving disk at the
entrance side of the circulation passage to force oil to the dam.
During rotation, the guiding and pumping actions of the oil supply
means is combined with the centrifugal force to urge oil from the
torque transmission gap to the dam. Especially, the pressure of oil
collected in the dam is increased certainly to thereby prevent
hunting. Also, flow through the gap is promoted to stabilize the
control over the torque transmission. This permits oil to pass
through the torque transmission gap in a shorter time. In this way,
the time for which heat is produced due to shear caused by torque
transmission is shortened. This suppresses increase in oil
temperature. The circulation of the oil through the whole internal
structure is made rapid and smooth. The result is that heat is
dissipated well. Therefore, the viscosity of oil is prevented from
dropping. This prevents reduction in the rotational speed of the
fan. Hence, it is unlikely that the engine is cooled
insufficiently. Thus, the novel fan fluid coupling controls the
rotation of the fan more adequately in response to the varying
ambient temperature for a long time.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical cross section of a temperature-controlled fan
fluid coupling according to the invention;
FIG. 1A is an enlarged cross section of main portions of the
coupling shown in FIG. 1;
FIG. 2 is a view similar to FIG. 1, but showing another fan fluid
coupling according to the invention;
FIG. 2A is an enlarged cross section of main portions of the
coupling shown in FIG. 2;
FIG. 3 is a partially cutaway enlarged cross section of main
portions of a further fan fluid coupling according to the
invention;
FIG. 4 is a cross-sectional view taken on line A--A of FIG. 3;
FIG. 5A is a vertical cross section of a still other
temperature-controlled fan fluid coupling according to the
invention;
FIG. 5B is a view similar to FIG. 1A, but showing a modification of
the coupling shown in FIG. 5A;
FIG. 6A is a front elevation of the driving disk of the coupling
shown in FIG. 5A;
FIG. 6B is a partially cutaway enlarged side elevation of the
driving disk shown in FIG. 6A;
FIG. 6C is a view similar to FIG. 6A, but showing the driving disk
of the coupling shown in FIG. 5B;
FIG. 6D is a view similar to FIG. 6B, but showing the driving disk
of the coupling shown in FIG. 5B;
FIG. 7A is a vertical cross section of a yet further
temperature-controlled fan fluid coupling according to the
invention;
FIG. 7B is a view similar to FIG. 7A, but showing a modification of
the coupling shown in FIG. 7A;
FIG. 8 is a partially cutaway enlarged cross section of main
portions of a further modification of the coupling shown in FIG.
7A;
FIG. 9 is a fragmentary plan view of the driving disk shown in FIG.
8;
FIG. 10 is a fragmentary vertical cross section of another driving
disk;
FIG. 11 is a fragmentary plan view of the disk shown in FIG.
10;
FIG. 12 is a fragmentary enlarged cross section of the labyrinth
mechanism in the enclosed housing of the coupling shown in FIG.
2;
FIG. 13 is a vertical cross section of the prior art
temperature-controlled fan fluid coupling; and
FIG. 14 is a graph showing the operating characteristics of the
coupling shown in FIG. 13.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the temperature-controlled fan fluid coupling
according to the invention is shown in FIGS. 1, 1A, 2, 2A, 3, and
4. A first specific example of this embodiment is shown in FIGS. 1
and 1A. A second specific example of the embodiment is shown in
FIGS. 2 and 2A. A third specific example of the embodiment is shown
in FIGS. 3 and 4.
In these figures, a rotating shaft 1 has a driving disk 7 rigidly
fixed at its front end. An enclosed housing consisting of a cover 3
and a casing 2 is held to the shaft 1 via a bearing B. A cooling
fan F is mounted to the outer periphery of the cover 3. The inside
of the enclosed housing is partitioned into an oil reservoir
chamber 6 and a torque transmission chamber 4 by a partition plate
5 having an outflow control hole 5' for controlling flow of oil
from the reservoir chamber 6 into the transmission chamber 4. The
driving disk 7 is mounted inside the torque transmission chamber 4.
A small gap is maintained between the outer portion of the disk 7
in the torque transmission chamber 4 and the opposite wall surface
of the enclosed housing including the partition plate 5, to
transmit torque. A valve member 8 opens and closes the outflow
control hole 5'. One end of the valve member 8 is riveted to the
surface of the partition plate 5 which is on the side of the oil
reservoir chamber 6. The other end is located at the position of
the hole 5'. A metallic support 11 is rigidly fixed to the front
surface of the cover 3. A temperature-sensing element 10 consisting
of a bimetallic strip is anchored to the support 11 at its both
ends. An interlocking rod 9 bears against the valve member 8 inside
the cover 3. As the ambient temperature varies, the
temperature-sensing element 10 deforms to move the rod 9 forward or
rearward, which in turn shifts the valve member 8.
A dam 12 is formed in a part of the inner wall surface of the
enclosed housing that is opposite to the outer wall of the driving
disk on which oil collects during rotation. An entrance port 13' is
formed near the upstream side of the dam as viewed in the direction
of rotation. The torque transmission chamber 4 is in communication
with the entrance port 13'. A circulation passage 13 is formed from
the torque transmission chamber 4 to the oil reservoir chamber 6 to
perform pumping function.
A hole 5" is formed in the center of the partition plate 5 and
extends through the plate. In an example having an idle oil
reservoir chamber as described later, the hole 5" connects the oil
reservoir chamber 6 with the torque transmission chamber 4 only at
a stop.
An annular idle oil reservoir chamber 14 (FIG. 2) can be positioned
on the side of the enclosed housing, if desired. The chamber 14 is
located radially outside the dam 12 and in communication with the
torque transmission chamber 4 formed in the inner wall surface of
the housing. The capacity of the idle oil reservoir chamber 14 is
equal to the amount of oil collected in both torque transmission
chamber 4 and the idle oil reservoir chamber 14 at a stop. As
particularly shown in FIG. 1A, a number of radially protruding fins
16 are formed near the outer periphery of the driving disk 7 on the
enclosed housing at least on the side of the dam 12. The fins are
located at least on the upstream side of the dam as viewed in the
direction of rotation. Preferably, the fins 16 are inclined at an
angle of .alpha. (see FIG. 4). More preferably, they are curved to
form receiver surfaces in the direction of rotation. As shown in
FIGS. 2 and 2A, recessed walls 16' have recesses formed at the same
position of the fins 16. The base portion of each fin 16 or the top
portion of each recessed wall 16' is formed substantially flush
with the inner side surface of the enclosed housing. Where the idle
oil reservoir chamber 14 is formed, the recesses extend into this
chamber 14. As shown in FIG. 3, a labyrinth mechanism may be formed
in the vicinities of the outer periphery of the driving disk 7 and
on the opposite wall surface of the enclosed housing to create the
torque transmission chamber 4. In this case, oil does not flow
smoothly, and the temperature of the oil increases. Further, when
the engine is restarted, the rotational speed increases
excessively. To prevent these undesired phenomena, it is desired to
form the fins 16 or the recessed walls 16' at least on the opposite
side of the labyrinth mechanism on the enclosed housing. Cooling
fins 15 protrude outwardly from the enclosed housing.
As described thus far, in the first embodiment of the novel
temperature-controlled fan fluid coupling, the numerous fins 16 or
the recessed walls 16' are formed on the wall surface opposite to
the driving disk 7 on the enclosed housing near the outer periphery
of the disk 7. Thus, during rotation, the fins serve as guide vanes
acting on the oil. Also, the oil is conveyed by centrifugal force.
In addition, the fins or the recessed walls perform pumping action
to force oil from the torque transmission gap to the dam 12.
Especially, the pressure of oil collected in the dam is increased
with certainty to prevent hunting. The flow of oil through the gap
is smoothened. This stabilizes the control action. Furthermore, the
oil passes through the torque transmission gap in a shorter time.
As a result, the time for which the mechanism undergoes shear and
is heated is decreased. This minimizes the temperature increase of
the oil. The oil is quickly and smoothly circulated through the
whole internal structure, leading to improved heat dissipation.
Hence, the viscosity of the oil is kept from falling. Consequently,
the ability to cool the engine does not drop. During prolonged
operation, the fan fluid coupling performs more appropriate control
function in response to the varying ambient temperature. If
necessary, the idle oil reservoir chamber 14 is also formed. The
fins 16 or the recessed grooves 16' are formed from the oil
reservoir chamber 6 to the idle oil reservoir chamber 14. This
enables the oil to circulate rapidly, whereby effectively
suppressing the unwanted increase of the rotational speed of the
driven fan. Also, the invention can be applied to a system where
torque is transmitted by the labyrinth mechanism. In this way, the
temperature-controlled fan fluid coupling is quite useful.
A second embodiment of the novel temperature-controlled fan fluid
coupling is next described by referring to FIGS. 5A, 5B, 6A, 6B,
6C, and 6D.
In these figures, a rotating shaft 1 has a driving disk 7 rigidly
fixed at its front end. An enclosed housing consisting of a cover 3
and a casing 2 is held to the shaft 1 via a bearing B. A cooling
fan F is mounted to the outer periphery of the cover 3. The inside
of the enclosed housing is partitioned into an oil reservoir
chamber 6 and a torque transmission chamber 4 by a partition plate
5 having an outflow control hole 5' for controlling flow of oil
from the reservoir chamber 6 into the transmission chamber 4. The
driving disk 7 is mounted inside the torque transmission chamber 4.
A small gap is maintained between the outer portion of the disk 7
in the torque transmission chamber 4 and the opposite wall surface
of the enclosed housing including the partition plate 5, to
transmit torque. A valve member 8 opens and closes the outflow
control hole 5'. One end of the valve member 8 is riveted to the
surface of the partition plate 5 which is on the side of the oil
reservoir chamber 6. The other end is located at the position of
the hole 5'. A metallic support 11 is rigidly fixed to the front
surface of the cover 3. A temperature-sensing element 10 consisting
of a bimetallic strip is anchored to the support 11 at its both
ends. An interlocking rod 9 bears against the valve member 8 inside
the cover 3. As the ambient temperature varies, the
temperature-sensing element 10 deforms to move the rod 9 forward or
rearward, which in turn shifts the valve member 8.
A dam 12 is formed in a part of the inner wall surface of the
enclosed housing that is opposite to the outer wall of the driving
disk on which oil collects during rotation. An entrance port 13' is
formed near the upstream side of the dam as viewed in the direction
of rotation. The torque transmission chamber 4 is in communication
with the entrance port 13'. A circulation passage 13 is formed from
the torque transmission chamber 4 to the oil reservoir chamber 6 to
perform pumping function.
A hole 5" is formed in the center of the partition plate 5 and
extends through the plate. In the example shown in FIG. 5B, the
hole 5" connects the oil reservoir chamber 6 with the torque
transmission chamber 4 only at a stop.
An annular idle oil reservoir chamber 14 (FIG. 5B) can be
positioned on the side of the enclosed housing, if desired. The
chamber 14 is located radially outside the dam 12 and in
communication with the torque transmission chamber 4 formed in the
inner wall surface of the housing. The capacity of the idle oil
reservoir chamber 14 is equal to the amount of oil collected in
both torque transmission chamber 4 and idle oil reservoir chamber
14 when the engine stops. Cooling fins 15 protrude outwardly from
the enclosed housing. A multiplicity of fins 7', 7" protrude
radially from the vicinities of the outer periphery of the disk 7.
In the illustrated example, the fins 7' and 7" are disposed
respectively ahead and behind the outer periphery. Further, the
fins are staggered each other. However, the fins are not restricted
to this geometry. In FIGS. 5A and 6B, the top of each fin 7' is
made flush with the torque-transmitting surface of the driving disk
7. As shown in FIGS. 5B and 6D, the top portion of each fin 7" may
be made to protrude from the torque-transmitting surface of the
driving disk. Communication holes 16 extend to the rear side.
If desired, in the torque transmission chamber 4, the vicinities of
the outer periphery of the driving disk 7 may be caused to radially
mesh with the opposite wall surface of the enclosed housing to form
a labyrinth mechanism. A number of fins 7' and 7" may be formed
close to the outer periphery of the driving disk 7.
As described thus far, in the second embodiment of the novel
temperature-controlled fan fluid coupling, the radially protruding
numerous fins 7', 7" are formed near the outer periphery of the
driving disk 7. During operation, centrifugal force produced by
rotation acts on the oil. Further, the pumping action of the
numerous fins forces oil from the torque transmission gap to the
dam 12, whereby the dam functions efficiently. The flow of oil
through the gap is smoothened. This stabilizes the control action.
Furthermore, the oil passes through the torque transmission gap in
a shorter time. As a result, the time for which the mechanism
undergoes shear and is heated is decreased. This minimizes the
temperature increase of the oil. The oil is quickly and smoothly
circulated through the whole internal structure, leading to
improved heat dissipation. Hence, the viscosity of the oil is kept
from falling. Consequently, the ability to cool the engine does not
drop. In this way, hunting is prevented. During prolonged
operation, the fan fluid coupling performs more appropriate control
function in response to the varying ambient temperature. If
necessary, the idle oil reservoir chamber 14 is also formed. Since
the oil is allowed to circulate rapidly, the unwanted increase of
the rotational speed of the driven fan as indicated by
characteristic curve A in FIG. 14 is more effectively suppressed.
In this way, the temperature-controlled fan fluid coupling is quite
useful.
A third embodiment of the novel temperature-controlled fan fluid
coupling according to the invention is shown in FIGS. 7A, 7B, 8, 9,
10, 11, and 12.
In these figures, a rotating shaft 1 has a driving disk 7 rigidly
fixed at its front end. An enclosed housing consisting of a cover 3
and a casing 2 is held to the shaft 1 via a bearing B. A cooling
fan F is mounted to the outer periphery of the cover 3. The inside
of the enclosed housing is partitioned into an oil reservoir
chamber 6 and a torque transmission chamber 4 by a partition plate
5 having an outflow control hole 5' for controlling flow of oil
from the reservoir chamber 6 into the transmission chamber 4. The
driving disk 7 is mounted inside the torque transmission chamber 4.
A small gap is maintained between the outer portion of the disk 7
in the torque transmission chamber 4 and the opposite wall surface
of the enclosed housing including the partition plate 5, to
transmit torque. A valve member 8 opens and closes the outflow
control hole 5'. One end of the valve member 8 is riveted to the
surface of the partition plate 5 which is on the side of the oil
reservoir chamber 6. The other end is located at the position of
the hole 5'. A metallic support 11 is rigidly fixed to the front
surface of the cover 3. A temperature-sensing element 10 consisting
of a bimetallic strip is anchored to the support 11 at its both
ends. An interlocking rod 9 bears against the valve member 8 inside
the cover 3. As the ambient temperature varies, the
temperature-sensing element 10 deforms to move the rod 9 forward or
rearward, which in turn shifts the valve member 8.
A dam 12 is formed in a part of the inner wall surface of the
enclosed housing that is opposite to the outer wall of the driving
disk 7 on which oil collects during rotation. An entrance port 13'
is formed near the upstream side of the dam as viewed in the
direction of rotation. The torque transmission chamber is in
communication with the entrance port 13'. A circulation passage 13
is formed from the torque transmission chamber 4 to the oil
reservoir chamber 6 to perform pumping function.
A hole 5" is formed in the center of the partition plate 5 and
extends through the plate. In the example shown in FIG. 7B, the
hole 5" connects the oil reservoir chamber 6 with the torque
transmission chamber 4 only at a stop.
An annular idle oil reservoir chamber 14 (FIG. 7B) can be
positioned on the side of the closed housing, if desired. The
chamber 14 is located radially outside the dam 12 and in
communication with the torque transmission chamber 4 formed in the
inner wall surface of the housing. The capacity of the idle oil
reservoir chamber 14 is equal to the amount of oil collected in
both torque transmission chamber 4 and idle oil reservoir chamber
14 when the engine stops. Cooling fins 15 protrude outwardly from
the enclosed housing. Radially arranged fins or convex walls 7' or
7" are formed on at least one of both surfaces of the driving disk
7 and located radially inside of the torque transmission gap to
form an impeller structure. If necessary, a plurality of
communication holes 16a are formed between the successive convex
walls.
In FIG. 12, the torque transmission chamber 4 is equipped with a
labyrinth mechanism. In particular, the vicinities of the outer
wall surface of the driving disk 7 are in radially mesh with the
opposite wall surface of the enclosed housing. In this case, oil
does not flow smoothly through the labyrinth mechanism. As a
result, oil temperature tends to increase. Also, when the engine is
restarted, the rotational speed of the fan tends to increase
excessively. To prevent these undesired phenomena, the driving disk
may have convex walls 7' or 7', 7" on the side of the labyrinth
mechanism.
As described thus far, the third embodiment of the novel
temperature-controlled fan fluid coupling has the fins or convex
walls 7' or 7', 7" radially protruding from the driving disk 7.
Thus, the disk has the impeller structure. During operation,
centrifugal force produced by rotation acts on the oil. Further,
the pumping action performed by the convex walls 7' or 7', 7"
forces oil out of and into the torque transmission gap. The flow of
oil through the gap is smoothened. This stabilizes the control
action. Furthermore, the oil passes through the torque transmission
gap in a shorter time. As a result, the time for which the
mechanism undergoes shear and is heated is decreased. This
minimizes the temperature increase of the oil. Circulation of oil
through the whole internal structure, including flow toward the dam
12, is made fast, leading to improved heat dissipation. Hence, the
viscosity of the oil is kept from falling. Consequently, the
ability to cool the engine does not drop. During prolonged
operation, the fan fluid coupling performs more appropriate control
function in response to the varying ambient temperature. At the
same time, the fan fluid coupling can be fabricated in small size.
Where the idle oil reservoir chamber 14 and the labyrinth mechanism
that especially augments the transmitted torque are mounted, the
oil is circulated through the circulation passage more quickly.
Consequently, the aforementioned undesired increase of the
rotational speed after restart of the engine can be prevented or
suppressed more effectively.
* * * * *